Hey guys, I just got a new Alco calcium battery for my XR8 and have noticed it doesn't seem to charge fully now. I don't have an alternator or battery warning light up. I checked the voltage whilst idling and it's around 13.5V. The volt guage on the dash displays anywhere between 13.5-13.9V whilst driving and drops closer to 13V when the headlights are on. I've had a look around and it seems that the ef V8 alternators are rated at 14V and 110 Amps. I've also read that calcium batteries need around 14.2V or more to charge properly.

My question is what's the best solution here - ditch the brand new calcium batt for a lead acid one, replace the voltage regulator, replace the alternator? Is it worthwhile getting a replacement regulator/ alternator if they're only rated at 14V but I need 14.2V to charge the new batt, and can the regulator output be adjusted if required?

I'm unsure whats the best answer on this one, any suggestions? Cheers

How are you checking voltage? Dash or multimeter?

I checked it with a multimeter to get the volts at idle, but could only go off the gauge on the dash whilst driving it and thats when I saw it fluctuate depending on load eg. headlights. I did check it with the multimeter with the headlights on now that I think of it and it was 13.3-13.4V.

First step is to measure voltage at cruise rpm accurately so you know if the alternator output is OK or not. Measure at alternator terminal and also battery +ve.

Good alternators usually put out about 14.5 volts at cruise rpm.

Got the missus to rev it to around 2000rpm and checked the voltage at the alternator. It was 13.6V at the alternator and 13.5 at the battery + terminal. The thermo's kicked in while I was checking it and the volts dropped down to 13.4V at the alternator and 13.3V at the batt.

Sounds like I'm up for a new alternator... Theres a few supposedly new ones on ebay for around $260+p/h, anyone know if they're any good or if they're dodgy and I should stay away? I've heard of people paying $600 so it sounds cheap to me.

I'd try getting a quote from a local sparky first. It may be as simple as a new set of brushes, cleaning the commutator or replacing a dud diode. Over here a sparky will do an on-vehicle test for nothing including a repair estimate. A full-blown quote usually costs a few $$$ if you don't proceed with the repair. But a good sparkies experience is helpful with your Ebay option as a fall back.

If a calcium battery isn't charged using a calcium charger to start off with the battery will only have like 80% of charge. A calcium charger actually pulses to reach the 100%. Maybe buy a decent calcium battery charger and see how you go.